As is well-known in the mechanical arts, any structure or body which is subjected to known or identifiable forces will tend to deform or deflect in a predictable manner. As with any other solid structures, this also holds true for electronic components which must be engaged with each other to establish desired electrical circuits. Electronic components, however, are of a unique concern because any unwanted deformation or deflection of an electronic component can result in unconnected or misconnected electrical circuits. Accordingly, the interest here focuses on some of the problems which are caused by structural deformations or deflections of interconnected electronic components. More specifically, the concern here is on the deformations or deflections of an electronic substrate, such as a printed circuit board, which occur when the substrate is engaged with a plurality of electrical contacts to establish desired electrical circuits.
Typically, an electronic substrate supports a complex of electrical circuits which are collectively or individually connected with electrical circuits external to the substrate. Frequently, such connections are with two or more other electronic substrates. In any event, it is normally the case that the electrical circuits on a substrate terminate at electrical pads which are located on a peripheral edge of the substrate. In most instances the edge of the substrate is linear and these pads are, therefore, typically aligned along the edge. Consequently, the connector which is used to establish electrical contact between electrical circuits on the substrate and electrical circuits which are external to the substrate is an elongated member that is engageable with the pads at the edge of the substrate.
Connectors which establish electrical connections with the substrate as mentioned above are generally elongated structures which support a plurality of cantilevered contact beams. Further, it is the normal practice to attach these elongated connectors to the substrate at points which are at, or very near, the ends of the elongated structure. The result upon attachment of the connector with the substrate is that the forces exerted by the connector on the substrate can be easily characterized. Specifically, the force distribution on the substrate for such an attachment includes concentrated loads at the end points where the elongated structure is attached to the substrate and a uniformly distributed load between the concentrated loads which is caused by the individual cantilevered contact beams urging against the pads on the substrate.
With a load distribution as described above, it is known that the substrate will respond in a predictable manner. Specifically, the substrate will bow across the distance under the uniformly distributed load and between the end points where it is subjected to the concentrated load. This bowing of the substrate, however, can have an adverse effect for the electrical connection between the contact beams on the elongated structure and the pads on the substrate. For instance, it is known in the electrical arts that there needs to be some minimal force between the contact beam and the substrate pad in order for there to be an effective electrical connection. If the substrate is bowed, however, the deflection of the substrate will distance the substrate from the elongated structure and thereby reduce the interactive force between the substrate and the contact beams cantilevered on the elongated structure. Thus, the required force for an effective electrical connection can not be insured and, indeed, may not be attained.
The present invention recognizes that whenever an electronic substrate and a series of spring-loaded, or cantilevered, contact beams are connected together, the result will be a distributed load on the substrate. The present invention further recognizes that any distributed load in combination with a concentrated load, or loads, will tend to bow or bend the substrate. The present invention, however, also recognizes that the distribution of uniform and concentrated loads between an electrical connector and an electronic substrate can be engineered to minimize the bowing of the substrate and, thus, enhance the electrical connections between these two structures.
In light of the above, it is an object of the present invention to provide a connector for balancing the forces between a plurality of electrical contact beams on a connector and a plurality of electrical pads on an electronic substrate, to establish a more secure electrical connection between the contact beams and the substrate. It is another object of the present invention to provide a balanced pressure connector which more evenly urges electrical contact beams into electrical contact with an electronic substrate in order to reduce or minimize deflections of the substrate. Yet another object of the present invention is to provide a balanced pressure connector which is simple to use, relatively easy to manufacture, and comparatively cost-effective.